1. Field of the Invention
Embodiments of the present invention relate generally to tape substrates. More particularly, embodiments of the invention relate to a tape distribution substrate having a pattern adapted to reduce an amount of electromagnetic interference (EMI) between distribution lines of the tape distribution substrate.
A claim of priority is made to Korean Patent Application No. 10-2005-0062904, filed on Jul. 12, 2005, the disclosure of which is hereby incorporated by reference in its entirety.
2. Description of Related Art
Conventional display panel assemblies include display panels, printed circuit boards (PCBs), and tape distribution substrates connecting the display panels to the PCBs. The tape distribution substrates transmit electrical signals from the PCBs to the display panels to drive various components associated with the display panels. Most display panels are connected to a gate PBC by a gate tape distribution substrate, and to a source PCB by a source tape distribution substrate.
FIG. 1 is a plan view of a part of a conventional source tape distribution substrate 10. Source tape distribution substrate 10 comprises a plurality of distribution lines for transmitting data to a display panel from a source PCB. Among the distribution lines are data distribution lines 13, which transmit data signals to the display panel. Data distribution lines 13 are arranged on a base film 11 of the source tape distribution substrate 10. Base film 11 has a chip mounting portion 11a on which a semiconductor chip is mounted. A protective layer 12 is formed on base film 11 to cover data distribution lines 13. However, protective layer 12 is not formed on chip mounting portion 11a. Protective layer 12 is formed on base film 11 so that portions of data distribution lines 13, which are connected to pads of the source PCB are left exposed. Pads 16-1, 16-2, and 16-3 that will be electrically connected to bumpers of the semiconductor chip are arranged on chip mounting portion 11a, and connected to respective pairs of data lines 13-1, 13-2, and 13-3 of data distribution lines 13.
Data distribution lines 13 include a plurality of pairs of data lines 13-1, 13-2, and 13-3 that divide data signals D1, D2, and D3 into pairs of data signals having opposite phases (D1(+), D1(−)), (D2(+), D2(−)), and (D3(+), D3(−)) and transmit the data signals. The pairs of data lines 13-1, 13-2, and 13-3 respectively include first and second data lines (13-1a, 13-1b), (13-2a, 13-2b), and (13-3a, 13-3b). First and second data lines (13-1a, 13-1b), (13-2a, 13-2b), and (13-3a, 13-3b) of data line pairs 13-1, 13-2, and 13-3 are respectively combined into single data lines through connection cells 13-1c, 13-2c, and 13-3c. 
Therefore, when the pairs of data signals (D1(+), D1(−)), (D2(+), D2(−)), and (D3(+), D3(−)) having opposite phases are provided from the source PCB, the pairs of data signals (D1(+), D1(−)), (D2(+), D2(−)), and (D3(+), D3(−)) are respectively input into first and second data lines (13-1a, 13-1b), (13-2a, 13-2b), and (13-3a, 13-3b) of the data line pairs 13-1, 13-2, and 13-3. The pairs of data signals (D1(+), D1(−)), (D2(+), D2(−)), and (D3(+), D3(−)) provided to the respective first and second data lines (13-1a, 13-1b), (13-2a, 13-2b), and (13-3a, 13-3b) are combined into single data signals D1, D2, and D3 through the connection cells 13-1c, 13-2c, and 13-3c, and then provided to pads 16-1, 16-2, and 16-3 of chip mounting portion 11a through data lines 13-1, 13-2, and 13-3, respectively.
In tape distribution substrate 10, connection cells 13-1c, 13-2c, and 13-3c are arranged between respective data line pairs 13-1, 13-2, and 13-3 to connect the respective first and second data lines of each pair. Each pair of first and second data lines distribution lines in a pair are arranged with a first distance P11 therebetween. In addition, each pair of data lines is arranged at a second distance P12 from a next pair. First distance P11 between first and second data lines of the same data line pair is larger than second distance P12 between adjacent data lines of different data line pairs. Because of the closeness of adjacent data lines transmitting different signals, EMI can occur between the adjacent data line.
FIG. 2 is a plan view of another part of conventional source tape distribution substrate 10. FIG. 2 illustrates a part of a power distribution line 14 for providing a power voltage Vdd and a ground voltage Vss from a source PCB to a display panel. Referring to FIG. 2, power distribution line 14 includes a plurality of sub-power distribution lines 14-1, 14-2, and 14-3, and a connection portion 14a for combining the sub-power distribution lines 14-1, 14-2, and 14-3. Connection portion 14a of power distribution line 14 is exposed out of protective layer 12 to receive a power signal such as power voltage Vdd or ground voltage Vss from the source PCB. Sub-power distribution lines 14-1, 14-2, and 14-3 are respectively connected to pads 18-1, 18-2, and 18-3 disposed on chip mounting portion 11a to provide predetermined power to a semiconductor chip that will be mounted on chip mounting portion 11a. 
Power distribution line 14 is divided into a plurality of sub-power distribution lines 14-1, 14-2, and 14-3 to supply power to the semiconductor chip mounted on the chip mounting portion 11a. Because sub-power distribution lines 14-1, 14-2, and 14-3 are combined into one line at connection portion 14a, as the lengths of sub-power distribution lines 14-1, 14-2, and 14-3 increase, the line resistance of these sub-power distribution lines also increases. In addition, since a plurality of sub-power distribution lines 14-1, 14-2, and 14-3 are formed adjacent to each other, EMI occurs between neighboring power distribution lines.
FIG. 3 is a plan view of yet another part of conventional source tape distribution substrate 10. FIG. 3 illustrates a dummy pattern and distribution lines adjacent to the dummy pattern on conventional source tape distribution substrate 10. Referring to FIG. 3, source tape distribution substrate 10 includes a portion having a high pattern-density in which a plurality of distribution lines 15 are arranged, and a portion having a low pattern-density. Dummy distribution patterns 20 are arranged in the portion having the low pattern-density. Dummy distribution patterns 20 include holes 21 in a stripe shape extending along a length direction of distribution lines 15. Since conventional tape distribution substrate 10 includes holes 21, line patterns extending in the same direction as the distribution lines are formed between holes 21, and thus, EMI occurs.